PANAJI: In a commendable achievement, five final year students of Don Bosco College of Engineering have constructed a rolling or curling bridge — considered the next big step in mobile bridge designs.

At present, the only such bridge in the world is operational in London where it spans an inlet of the Grand Union Canal, towards the head of Paddington Basin. It was designed by the award-winning Heatherwick Studio, working with structural engineers SKM Anthony Hunts and installed in August 2004.

At first glance, the rolling bridge built by the Don Bosco students seems to be an innocuous steel structure. But as its name suggests, it can slowly roll up till its ends meet to allow passage from underneath. The four-metre-long and 0.6-metre-wide prototype comprises eight triangular segments that fold towards each other to form an octagonal structure. A full fledged model can be as long as 12m .

Under the guidance of assistant professor Chetan Gaonkar, Froylan Gracias, Mikhai l Estibeiro, Alvan Fernendes, Samson Reberio and Kevin Thomas, brainstormed and laboured for a year to design the short-range pedestrian bridge. While the one in London uses electricity and hydraulics to function, the indigenous prototype has gone a step ahead. The engineering students have devised an eco-friendly way to generate power to operate the bridge that works on pneumatic cylinders.

Explaining the uniqueness of their prototype, Gracias says, "The main difference is the medium used to transmit power. The bridge in London uses hydraulics or liquid oil to transmit power, whereas our bridge uses compressed air taken from its surrounding. The pneumatic cylinders are used to generate power from compressed air. This makes it is more eco-friendly, plus it does not make much sound and does not require large amount of space for liquid storage."

Such bridges can be used to connect ships to ports, provide pathways to canals creeks, and canyons, and even link buildings in mid air. The unique mechanism of the bridge can be a major tourist attraction as well. In fact, the workings of the rolling bridge in London are put on display twice a week in the afternoon to delight tourists and commuters. "We have also patented the idea and are planning to send it to various bridge design competitions across the country," says an excited Gracias. Assistant professor Gaonkar, who mentored the students, says the contraption requires fine tuning. "As of now, the design mechanism can support and maintain the balance and position of the retractable part of the bridge. It now has to be analysed for static and dynamic loading, which requires knowledge of structural engineering." — By Sidharth Bharadwaj